This invention relates to a transcutaneous access device. It relates more particularly to a device of this type to facilitate access to the body through the skin by catheters and similar percutaneous devices.
There has of late been increasing use of catheters to provide prolonged or repeated access to the internal organs of chronically ill patients. For example, catheters are used to access a patient""s venous system for the administration of intravenous (IV) fluids, antibiotics, and chemotherapy. Catheters are also implanted in patients who require repeated access to the peritoneum for peritoneal dialysis.
Other than occlusion, the most common complications arising with long-standing implants are exit-site infection, tunnel infection, local abscesses and even sepsis. Many of these complications arise because the skin adjacent to the catheter does not heal to form a tight barrier to infection. Rather, epidermal cells tend to invaginate or migrate inward along the catheter and never form a tight biological seal around the catheter. Also, tunnels are created through which body fluids may exude thereby creating a site for infection.
In an attempt to overcome these problems, a catheter has been devised which includes a button-like skirt with a raised neck and a central hole for accommodating a tube. The tube has a corrugated segment extending above the button neck which allows the external portion of the tube to be flexed so as to absorb shocks. The skirt, including a portion of the neck thereof, is covered with a porous material, such as polyester velour, to allow for cell infiltration. When that device is implanted, the epidermal cells tend to migrate or invaginate downward along the neck to the skirt where they form a biological seal with the collagen and subcutaneous tissue growth on the porous covering of the button; see U.S. Pat. No. 4,886,502.
While that concept was relatively successful in animals, it has had limited success in human trials because normal body motions caused stretching of the tissue adjacent to the catheter and exerted torsion on the catheter. Such movements of the tissue relative to the button, which is held stationary by the external segment of the catheter tube, results in disruption of the biological seal between the catheter and the adjacent tissue. Such disruption may also occur when the external segment of the catheter tube is moved accidentally or intentionally when connecting and disconnecting the catheter tube to the infusate source.
Accordingly, the present invention aims to provide a transcutaneous access device for a catheter which should circumvent most of the problems caused by relative movement of the catheter and the tissue surrounding the catheter.
Another object of the invention is to provide a transcutaneous access device which, when implanted, provides a tight biological seal between the device and adjacent tissue.
A further object of the invention is to provide a device of this type which reduces the risk of infection.
A further object is to provide such a device which allows a high fluid flow rate through the device.
Yet another object of the invention is to provide a transcutaneous access device which is relatively easy to manufacture in quantity.
Other objects will, in part, be obvious and will, in part, appear hereinafter. The invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.
The transcutaneous access device of this invention comprises a flat button with an opening therethrough and an integral upstanding tubular neck in registration with that opening. Formed as an integral extension of that neck is a flexible, extensible sleeve e.g. elastic tubing or a bellows, whose free end is terminated by a collar which connects to a conventional access catheter whose catheter tube extends all the way through the lumen formed by the sleeve or tube, neck and button of the access device.
In accordance with the invention, the lumen of the present device is large enough to provide appreciable clearance between the walls of the lumen and the access catheter so as to minimize contact between the access device and the access catheter. Thus, when the device is implanted, the collar and upper end segment of the catheter tube are free to move relative to the button and surrounding tissue.
In one preferred embodiment of the invention, the access device is permanently connected, via the free end of the sleeve, to the catheter. In another embodiment, two similar access devices are positioned back to back on the catheter with the free ends of their sleeves connected to the catheter, preferably such that the sleeves are in a collapsed condition. Another embodiment provides a high fluid flow rate through the device.